Motorists will be able to fill their tanks with greener fuels when a new initiative comes into force in the UK from tomorrow.

The move is known as the Renewable Transport Fuel Obligation (RTFO) and requires 2.5% of all road fuels sold to come from biofuels, rising to 5% by 2010. Motorists will fill their vehicles as normal, but the change is expected to save 2.5million tonnes of carbon dioxide by 2010.

It is part of a package of measures being taken to reduce the impact of transport on the environment.

The UK has gone further than any other country to give fuel suppliers a real incentive to produce sustainable biofuels that do not harm the environment. Suppliers are required to produce sustainability reports including information on where their biofuel crops come from and the level of carbon savings they will achieve. The Renewable Fuels Agency will publish these reports and compare the performance of transport fuel suppliers.

Alongside this, a review into the indirect impacts of biofuels has already been announced by Ruth Kelly to ensure that the full economic and environmental impacts of biofuel production are taken into account in the formation of UK policy beyond 2010.

Transport Minister Jim Fitzpatrick said:

"Making it easier for motorists to use greener fuel is an important step towards reducing carbon emissions from transport. It should help save millions of tonnes of carbon dioxide in the coming years.

"But we must do all we can to ensure biofuels are produced sustainably. We know people are concerned about the environmental risks associated with expanding biofuel production and we take those concerns very seriously.

"That is why we want to introduce mandatory standards as soon as possible to guarantee that biofuels don't cause deforestation or food shortages and we are leading international work to do this. In the meantime, we require suppliers to produce sustainability reports, providing an immediate incentive for them to source biofuels responsibly."

Phil Woolas, Minister for the Environment said:

"Emissions from transport need to go down if we are to make serious headway in tackling dangerous climate change and this initiative has the potential to deliver considerable carbon savings.

"Obviously sustainability needs to be at the heart of all biofuel production and it will remain at the forefront of all policy development in this area. We must be able to produce biofuel without causing a negative impact on our natural environment."

The Government has also recently published a body of research as a contribution to the debate on the wider sustainability impacts of biofuels.

The first, a review of work on the environmental sustainability of international biofuels production and use, commissioned by Defra, is an appraisal of the current evidence of the opportunities and threats from biofuel production.

The second considers the possible impact of the RTFO on users of tallow. It suggests that turning tallow into biodiesel does not deliver any net environmental benefits compared to the current uses of tallow.